This invention relates to a four-cycle spark ignition internal combustion engine having, for each cylinder, a single sleeve which reciprocates and rotates to open and close intake and exhaust passages.
Sleeve valve engines have historically produced high efficiency, partly due to low friction, with excellent durability and power. To these, this invention introduces the characteristic of low pollution emissions by exploiting its ability to:
a. induce high turbulence with no squish area and low pumping losses, PA1 b. incorporate more well-placed spark plugs, PA1 c. utilize an optimally shaped combustion chamber, PA1 d. provide a uniformly warm combustion chamber without knock and NO.sub.x problems due to the presence of a very hot exhaust poppet valve and the hot combustion chamber area surrounding it, and PA1 e. readily incorporate scavenging. PA1 a. those seeking to eliminate problems having to do with the sealed space above the sleeve which, in the Burt design, tends to accumulate sludge and carbon, PA1 b. those proposing various mechanisms to drive the sleeve in a path similar to that described in the initial Burt design, and PA1 c. those seeking to improve intake passages.